Steam turbine apparatus



Sept. 8, 1942. R. HERTL 2,294,983

STEAM TURBINE APPARATUS Filed April 29, 194i ATTORNEY -v 30 F7619; 3ROBERT I RTL Patented Sept. 8, 1942 STEAM TURBINE APPARATUS RobertHertl, Lansdowne, Pa., assignor to Westinghouse Electric & ManufacturingCompany, East Pittsburgh, Pa., a corporation of Pennsylvania ApplicationApril 29, 1941, Serial No. 390,863

4 Claims.

My invention relates to an elastic-fluid turbine wherein the rotor andthe cylirl'der define chambers separated by blading and it has for anobject to provide apparatus of this character in which the equilibriumpassage or conduit connecting the chambers includes a passage formed ina nozzle vane or block so that the length of the turbine may beshortened and its critical speed raised.

With a large steam turbine of the high-pressure and high-temperaturetype having a full peripheral impulse stage, the dummy may be locat-edso close to the impulse Wheel that there is little, if any, space leftfor an equilibrium space or passage. To answer this need, in accordancewith the present invention, the nozzle block or a nozzle vane, or apartition wall or rib, is formed to provide a portion of the equilibriumpassage, it being remembered, of course, that an equilibrium pipe orpassage is necessary to avoid excessive end thrust and consequent thrustbearing trouble or failure. If, with a full peripheral admissionturbine, conventional practice is followed, it becomes necessary tolengthen the turbine sufficiently so that the dummy is spaced from theimpulse wheel adequately to accommodate the equilibrium pipe or passage;however, increasing the length of the turbine lowers the critical speed,involves increased expense and waste of space, and, because of criticalspeed requirements, may make the design of a large turbine prohibitive.

A further object of the invention is to provide an impulse stage havinga single row of movin blades with an equilibrium passage, or conduit forconnecting together the spaces at the inlet and outlet sides of theblades and wherein one or more nozzle vanes of the stage accommodateportion or portions of the equilibrium passage.

These and other objects are effected by my invention as will be apparentfrom the followin description and claims taken in accordance with theaccompanying drawing, forming a part of this application, in which:

Fig. 1 is a fragmentary, longitudinal, sectional view of a portion of aturbin showing the improved equilibrium passage applied thereto;

Figs. 2 and 3 are enlarged detail sectional views, and are taken alongthe lines II-II and III-III of Figs. 1 and 2, respectively;

Figs. 4, 5, 6 and '7 are detail sectional views showing a modified formin which a vane itself has a portion of the equilibrium passage;

Fig. 8 is a detail sectional view showing a order to accommodate aportion of the equilibrium passage; and

Fig. 9 is a detail sectional View of a Rateau stage having anequilibrium passage connecting the spaces at opposite sides of theWheel, the passage having portions thereof formed in nozzle vanes.

Referring now to the drawing more in detail, in Fig. 1 there is shown aturbine rotor l0 and a cylinder H defining chambers l2 and i3 separatedby the blading l4 supplied with steam at suitable velocity by means ofnozzle passages 15 defined by nozzle vanes I'6 carried by the nozzleblock l1.

As shown in Fig. 1, the chamber 12 is arranged between the rotor impulseportion I ia carrying the moving blades of the blading l4 and the dummy[8. In order that the dummy may be subjected to the same pressure asthat existing in the chamber 13 at the discharge side of the blading 14,it is necessary to provide one or more equilibrium pipes or passages,one being shown.

Because of the relatively close spacing of the special nozzle vanehaving greater axial length in dummy l8 and the impulse stage in Fig. 1,the nozzle block has a radially-extending passage 20 aligned with radialpassages 22 formed in the block H. The cylinder has a passage 23 formedtherein, one end of the passage 23 communicating with space I3 and theother end communicating with the outer radial opening or passage 22.Thus, there is provided, an equilibrium passage having a portion thereofextending radially of and incorporated in the nozzle block.

As shown in Figs. 1 and 2, the nozzle block portion 29 of theequilibrium passage is provided by a pipe section 2| arranged ahead ofthe inlet edge 25 of one of the nozzle vanes.

In Fig. 3, there is shown in detail how the component elements of thenozzle block structure are connected together, the inner and outer ends.of the vanes 16 being connected to inner and outer portions of thenozzle block I! in any sui able manner and the pipe 2| having its endsfitting closely portions of the block I! provided with the al'gnedpassages 22 and preferably being welded, as shown at 26, to the edge ofthe adjacent outer and inner members of the nozzle block to preventleakage.

In Figs. 4 to 7, inclusive, there are shown nozzle block structureshaving vanes l6 defining nozzle passages 15 and wherein one of the vanesis modified so as to incorporate the radial passage portion 20 of theequilibrium passage.

In Figs. 4 and 5, the passage 20 is defined by a pipe Zia incorporatedwithin the structure of the vane, the ends of the pipe preferablyextending through inner and outer portions of the nozzle block andproviding the passage portion 20.

In Figs. 6 and '7, the passage 28 is defined by an opening extendinglongitudinally of the vane, the ends of the passage aligning with radialopenings 22 formed in the nozzle block structure II. The welds 28provide for sealing of the joint between adjacent ends of the passagesand I5.

In Fig. 8, there is shown a further form of the invention representing acombination of the features of Figs. 4 and 6. In this view, one of thevanes lfia has substantially greater axial length than the other vanes,the relatively greater axial length making it possible to provide apassage a which is of curved and elongated section.

In Fig. 9, there is shown a form of the present invention particularlysuitable for a single row impulse or Rateau turbine stage. This type ofstage incorporates alternately arranged nozzle vane structures ordiaphragms 29 and turbine dis-cs or wheels 39, each diaphragm 29preceding a Wheel 30 having nozzle vanes 3| providing nozzle passagesfor supplying steam at suitable velocity to the blades or buckets 32carried by the succeeding disc or wheel 3%. In this view, there is shownone of the discs or wheels 30 with diaphragms-preceding and succeedingthe latter. As there may be a difference in pressure between the steaminlet and outlet sides of the blades or buckets 32, it is desirable toprovide an equilibrium passage to assure of the maintenance of identicalpressures atv opposite sides of the Wheel or disc. Accordingly, thediaphragms at either side of the wheel or disc 38 have radial passages22a formed therein and aligned and operatively continuous with theradial passages 201) formed in the vanes 3!. The outer ends of thepassages 22a are connected by an axially-extending passage 23a havingportions thereof formed in the diaphragms and in the cylinder structureI la.

The expression nozzle vane structure, as used herein embraces the nozzleblock and the vanes collectively; and, when it is stated that suchstructure has a passage formed therein, this covers either formation ofthe passage in a vane or in a separate pipe or structure.

While the invention has been shown in several forms, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various other changes and modifications without departingfrom the spirit thereof, and it desired, therefore, that only suchlimitations shall be placed thereupon as are specifically set forth inappended claims.

What I claim is:

1. In a turbine, a cylinder and a rotor providing chambers therebetween,blading separating the chambers, nozzle vane structures cooperating withthe blading, and means including a passage formed in a nozzle vanestructure to provide an equilibrium passage connecting the chambers.

2. In a turbine, a cylinder and a rotor providing chambers therebetween,blading separating the chambers, a nozzle block including nozzle vanesdefining nozzle passages for supplying elastic fluid to the blading, andmeans including a passage formed in the nozzle block to provide anequilibrium passage connecting the chambers.

3. In a turbine, a cylinder and a rotor providing chambers therebetween,blading separating the chambers, a nozzle block attached to the cylinderand including vanes defining nozzle passages for supplying elastic-fluidto the blading, and means including communicating passages formed in thestructures of the cylinder and of the nozzle block and extending axiallyof the structure of the cylinder and radially of the structure nozzleblock to provide an equilibrium passage connecting the chambers.

4. In a turbine, a cylinder and a rotor providing chambers therebetween;an impulse stage including stationary and moving blades carried by thecylinder and by the rotor, respectively, and a nozzle block providedwith nozzle passages for supplying elastic fluid to the blades; a dummyconstruction cooperating with the rotor and with the cylinder andproviding for the imposition of steam thrust on the rotor; one of saidchambers being arranged between the dummy construction and said stage atthe elasticefiuid inlet side of the latter and theother chamber beingarranged at

